The need to heat structures to control the interior temperature has been a requirement for modern housing for many years. One of the current popular methods to heat a structure is with a furnace that burns either oil or natural gas. Due to the increasing cost of fossil fuels, the operating efficiency of such furnaces has become a greater and greater concern.
One common method of increasing the fuel efficiency of a burner within a furnace has been to utilize a blower assembly to induce a draft through the furnace to draw the heated air and the products of combustion through a heat exchanger and exhaust the gases through an exhaust pipe. The blower assembly includes a rotating impeller that creates a source of negative air pressure. The negative air pressure in the bower housing increases the draft such that the heated air and the products of combustion can travel through as tortured a path as possible to increase the amount of heat removed from the exhaust gases within the heat exchanger. The increase in the flow of air thereby increases the heat transfer and generating capacity of the burner while simultaneously using less fuel per BTU of heat generated. The addition of a blower assembly to a furnace generates a rating of about 80% fuel efficiency in a modern furnace. Thus, it is clearly a necessity to introduce a blower assembly to a modem furnace to maintain minimum desired efficiency standards.
In an 80+ furnace (which refers to a furnace that is at least 80% efficient), the temperature of the exhaust gases withdrawn from the furnace are  typically in the range of 350° F. and these gases are drawn into the open interior of the blower housing by the rotating impeller. As such, the blower housing for an 80+ furnace must be durable enough to withstand the heat and is thus typically made from sheet metal. Further, the impeller utilized with such a blower assembly must also withstand the same temperature and is typically also made from a metal material.
Currently, an 80+ blower assembly utilizes one of two types of impellers. The first type of impeller is referred to as a squirrel cage impeller. A squirrel cage impeller includes a metallic, circular back plate having a plurality of forward curved impeller blades extending perpendicular to the generally planar back plate. Each of the impeller blades extends radially from the center of the back plate out to the circumferential outer edges of the back plate. The plurality of individual impeller blades are secured to the back plate individually by a metal forming technique. Additionally, the axial outer edges of the impeller blades are secured to each other by an inlet ring that is individually fixed to the axial outer edges of each of the impeller blades. During the construction of the squirrel cage impeller, numerous metal working steps are required to attach the impeller blades to the back plate and finally secure the impeller blades to each other by the inlet ring. Thus, the labor and material costs to produce a squirrel cage impeller are significant.
The second type of impeller currently utilized in an 80+ furnace is a stamped impeller formed from a single sheet of metal. In the currently available stamped sheet metal impellers, each of the impeller blades extends radially from a central location. The height of the impeller blades is dictated by the number of individual blades, since the material between the blades is used to form the axially extending blade portion of the blade. Although the radial blade, one-piece sheet metal impeller reduces the cost of producing the impeller as compared to a squirrel cage impeller, the performance characteristics of the currently available single piece stamped sheet metal impellers do not meet current performance standards and thus has limited the use of such impellers in blower assemblies. 
In addition, many currently available blower assemblies include a slinger fan mounted to the motor shaft and positioned to the exterior of the impeller cavity created by the blower housing. The slinger fan includes a plurality of fan blades that rotate along with the motor shaft and create a flow of air over the drive motor to both cool the motor and create a buffer of air between the heated exhaust gases in the impeller cavity of the blower assembly and the operating components of the drive motor. Although the slinger fan creates the desired cooling effect, the slinger fan increases the drag on the rotation of the motor shaft and thus requires a larger motor size to create the desired air flow characteristics by the impeller included in the impeller cavity of the blower assembly. Further, the slinger fan increases the material and assembly costs of the blower assembly.
The present invention addresses the problems identified above with a novel and cost efficient solution. The present invention solves the above stated problems with an easy to manufacture and assemble solution that has eluded manufacturers for years.